Hi Dave, you saved my ass with this one or the RE20 of my client! I think I may found a fix for collapsed diaphragm, at least for those who has a loose phase plug: I removed the capsule completely, open it up as you have shown in the video, placed the capsule without resonance cap (phase plug cover) upside down on a fat rubber o-ring that touches the border of the diaphragm. Put that on peace of wire mesh on the top of the empty RE20 housing. Then put carefully some non magnetic weight (my x-acto knife is aluminum) through the back opening on the loss phase plug and force the diaphragm in an outward position. Then I took a heat gun adjusted to 100ºCelsius, with the lowest fan setting and blow from beneath at the diaphragm (via the housing with the capsule on top) for about one minute. Let it cool down, with the diaphragm still under tension. That should help with the collapsing part, but it is always a good idea, to clean the diaphragm from any metal dust that is attracted by the magnetic gap. That lets the diaphragm relax and brings back the bass. Liebe Grüsse Benno
Friend, firstly, greetings from Brazil!! Second: thank you very much, I'm really happy to be able to save my mic. I glued the heart to the mic. follow the game! You were a conductor.
You have explained the workings of the capsule more clearly than any engineer I've worked with at EV. That capsule is sealed and airtight much like how the RE-16 et al must be to maintain their advertised performance. When you break the terminating cavity free you undid that air seal. I believe the tubes are aluminum not brass. (could be wrong) ..we called them "cigarettes" and they've changed over the years in how they're "tuned." The "rotting foam" inside the capsule is a damping plug and we use airflow and a meter to tune it (with the diaphragm removed) to a specified impedance. I agree, the older models which used fiberglass are far superior in that they do not rot and they can be reused/retuned. The smart cookies playing along at home may have concluded that they can replace the foam that rotted out with fiberglass, but what size? how to tune? Do you leave it empty? How is the low end response, more/phatter low end or is it even discernible? I have a sneaking suspicion we're going to end up with a 2nd hand market of bottom heavy mics out here aren't we :D (that might be a good thing) If you get any ISO or other solvent on that voice coil it may fall apart as it is an air coil held together with an adhesive that is sensitive to alcohol. The cloth which is adhered to the back of the pole piece (loose disk) is tuned with air-flow and a varnish that may or may not change with QuTip and alcohol cleaning. Completeley fucking metal repair approach \m/ I saw them doing similar on groupdiy and am thoroughly impressed at the solution. Seriously awesome! While I do NOT condone this method, one slip up with that glue and it's curtains, if you find the outcome is adequate I'm stoked for ya and for finding a field repairable solution that is "good enough." Dave, have you sent one of your repaired mics into Bosch/EV and had them sweep it on the factory floor to see how close to spec your repaired mics are? Thoroughly interested. I could help facilitate. Bless up 🙏 inspired me to make some vids and help anywhere I can....kinda buried in repairs tho 😊 (sorry if I haven't returned emails I've been watching to see if Dave had a more expedited solution which I find the answer was no but it was very impressive and can't hate on that at all)
Thank you for all the great info! Yeah, this is a last ditch fix as I believe if this fails, the only other option is to replace the capsule I do believe there could be some shifts due to the repair, it does appear that the broken seal gets pretty well or very well re sealed as the old glue seems to act like a gasket to some degree. I think I recall the XLR male on the RE16/15 being glued as well. If that is the case, now I understand why, the air leak. Possibly it was a diff mic with the red glue on the XLR. Thanks again and really appreciate the comments and knowledge!
Hey dave , mezmorizing vid , u have the hands of a surgeon, how in blue blazes u remember the inner workings of these microphones just astounds me , consider my mind blown , awsome!!!!!!!!!!!!!!!!!!!!
Thank you so much! I had my mic with that problem for years and there seemed to be no fix for that. Your video was extremely helpful and now I have a fully working PL20/RE20 again.
What a pain! I had a PL20 with that problem that I wound up selling as non-working due to the cost of repair. I have 3x RE320s that I like very much but this video has convinced me to never buy another.
@@DaveRat it was a head scratcher as it was in bits with snapped wires everywhere to this daughter board attached to the rear port tube - and all I had was a low res circuit diagram from the grainy brochure pdf you can find on line. Great mics tho!
Thank you for this! I have an RE20 here that has started to do intermittent pops and static sound. Using this video I opened up the back and saw the green wire had been squished so hard somehow that some of the metal was coming through the wires insulation. I didn't want to deal with trying to replace the wire, so I just wrapped a bit of electrical tape around it to see if that fixes it. So far so good! This mic just lives on a boom stand on my desk, so hopefully the fix will work for a while.
Regarding the 3rd video in the series I felt it fair to share my comments for the public to digest: Very well done sir 🙏 Regarding your "honky" mic: sweep the filter circuit's frequency response and look for a deep notch where you are hearing the honk, if you don't see that notch in the passive eq that is why it sounds "honky." It's very possible the diaphragm is stuck, sometimes they can be unstuck sometimes the diaphragms are too far gone/damaged. Sometimes it's the voicecoil itself that is starting to fall out of shape or is pinched in the gap in those cases it's new voice coil time. Sometimes it's debris in the gap preventing the coil from moving and holding the diaphragm in a restricted state. This debris is often the old glue crust from the adhesive which used to hold the pole piece to the magnet. Microphone won't pass a freq response within limits (might still sound good) if not air tight. HPF components are the inductor only. If it goes open it can be rewound with #40AWG magnet wire, fill the bobbin. Less turns less rolloff more turns more rolloff. Modern PCB version can be rebuilt too but less common to fail. If microphone is in permanent "rolloff" check that the switch isn't stuck closed. There are better ways to route the wires than the factory method of folding them up in the rear cup making future disassembly much easier with zero downside in performance. Blue loctite 243 on the 9/64 rear cup screw may or may not help with accidental twisting when installing/removing from a 309a. That aluminum triangle bracket is really soft, don't over torque that screw or you will crack and break it. The name dB is great 🥰 2020 put me years, literally years behind in repairs but I'm slowly catching up.... sorry everyone. Surely if you've watched this video you can appreciate the effort that it takes to repair, and sometimes it doesn't go this smoothly as Dave makes it look easy ☺
Dear Dave! I can't thank you enough for this excellent video showing me how to save my RE20! I had it lying around for a few years, because I had realized that the foam was not the only issue. I did as you showed and everything work out fine. I was very critical of the super glue advancing into the tiny spaces between the disc and the magnet by itself, but it really does and the thing is stuck tight now! I didn't have the plastic thing to stuck onto the super glue bottle so I used a thin wire and transported tiny drops of the glue onto the inner edges of the magnet and the disc. Worked! I am so happy I got this one working again. Greetings and alle the best wishes from Hamburg, Germany, where the Beatles made it big, my friend!
YES!!! I have a vintage RE-20 with this exact issue. I've hat it sitting in a box for 10 years because I thought that you had to go through the front. AMAZING! CA nozzles on order!👽
I’m loving these mic repair videos, Dave. For some reason 🤣 we have a similar mic collection so your time and experience are of great benefit to me. Thanks so much!
Fascinating, excellent to see this. I have one that if one end is raised, it feels like the entire capsule slides to the other end. Doesn't sound like the phase plug has moved. Early 90s version of the RE20. Thanks for the specifics, especially re: the tools used. Mike
So it seems that the AKG D19 Influenced every mic that came after it... the 57 and especially the EV MICS with the actual tubes and ports. The D19 is hands down an awesome mic.
Greetings from Switzerland! I really like your videos and that you let other people know about all the knowledge you made over the years. I would really like to see a AKG D12 repair video. There's so much to say about these mics - and everyone with experience has some other new tricks..... :-)
@@DaveRat cool! Well, as far as my experience goes: These AKG mics are very very complicated. Their diaphragms are so big and thin, they can cause a lot of problems....
@@DaveRat Yes D12E , it will super cool , those mic loss some bottom end , but always affraid to dissasemble ...hope you will make a video . Super Job , i will try for my RE20 that have a rattling problem on my kick ...On video i saw that you press firm on the membrane , it can't break ?
Thank you so much for this info Dave: I ended up putting a replacement cartridge into a very similar vintage mic when I found the inner phase disc was bouncing around...look forward to seeing the reassembly video!!
This is a long shot, but after 6 years of pulling an old RE20 with the rattle from my repair pile, I finally was able to remove the set screw. I was super excited to follow along with this video and fix it, but for some reason the whole head wont unscrew. It gets about a 1/4 turn before seizing up. I think it may be some of the windscreen foam that got into the threads some how? Have you ever run into this issue???
The set screw tends to damage the threads and make it not unscrew if it was tightened really tight. I would drop a bit of oil down the set screw hole and work the grill back and forth and it should come apart unscrew
I tried the oil and it helped, but eventually had to use 2 belt wrenches to finally get it off. The rest of the repair was so easy thanks to your videos. Thanks so much for doing what you do!!!!@@DaveRat
The foam is pretty thin on the sides and is mainly shock mount and dust protection, any open cell thin foam will work and the sound impact will be non existent as long as the foam is not crushed to cause the cells to close. Open cell foam has no impact on low frequencies which is what comes in the sides of the mic. The front foam is a different story as it is thick, like an inch or so. It is mainly to add distance from grill to capsule, pop protection and dust protection The front foam should be very open cell. And the more open, the clearer the HF will be. I use a loosely rolled thinner open cell as you will see in the video that will let a bit more HF through than the original foam.
Outstanding video, Dave. I learned quite a bit about my own mic! I was not aware of the loose internal phase plug issue (mine isn't that way, fortunately), but now I know how to fix it. Thanks!
Just a tiny amount to bleed in between the disc and the top of the magnet. You are just gluing down the disk and barely any glue is needed. Do not get glue on the diaphragm or let is leak to the voice coil or the mix is ruined
@@DaveRat Thank you.... My problem is that I have a hard time picturing what it looks like in there. Is this correct: you go in and pass through the donut hole of the magnet and then just drop glue on one spot (any spot) where the pole piece makes contact with the magnet. The original adhesive would have been between the pole piece and the magnet, but I would just be adding a blob where they meet (via my hand pushing the pole down against the magnet). Sorry if I am getting this all wrong! Just trying to understand. Thank you!
Yeah that's right I believe. You are gluing the disc to the top of the magnet and you're going to drop a tiny bit of glue between the disc and the magnet where they get glued together and the super glue Will automatically spread at that junction where they meet by nature as liquids do when they encounter two things close together. The glue doesn't need to go all the way around it just needs to have a small amount applied to where the disc meets the top of the magnet and it'll spread inside of there on its own
Hi, Great video, so much so, I took on myself to delve into attempting to dismatle a very old PL20. Unfortunatley the post is broken. Not sure if I did it as I took care to lift and not twist the plug housing off the main body, but the underside has some scoring which would suggest that it has been twisted. I appreciate if you have any suggestions on how work around the broken post issue. In the meantime a good clean up and some new foam is in progress. Many Thanks for sharing your knowledge & experince.
For the broken post, I have fixed that before using a threaded machine screw that fit the hole and cut the head off and to length. That said, it is not a critical part. I believe it reduces RF and since these mics were/are used a lot for radio stations, RF is a concern more so that when used in other applications. It serves to align the bottom to the top rotation, and forms a small inductor. Make sure the wire is connected but beyond that, you will never notice a difference if it's floating and broken on there
i came back to re-watch and see if you mentioned the hex size to remove top screen, and i found that did. .09mm, i wonder if thats the same as a 0.035"? the set i have only goes down to .050. pretty small, but not small enough. i'll have to order it i guess.so glad you made these videos, thanks.
Thanks for the explanation. Just wondered why after all these years they didn't come up with a solution for the foam or the loose disc? Or did they already with newer versions and I just missed it?
Yeah, we are seeing issues that they did not predict or plan to prevent happening 20 or more years down the road. Adhesive's and foams have come a long way since way back then. Also changes to things like foams not lastonger but nearly always change the sound which may not be a loved change by all.
Could you do a strip down and rebuild of an RE-15 - if they can be taken apart of course? I bought one for use in my Elvis tribute and, yes, the foam had rotted. I cleaned it out and replaced it by simply removing the grill but that’s all. I’d really like to see inside it, if possible, to see how/if I can improve the sound. Or, as it actually works and I now use it in the act, would it be best to simply leave well enough alone?
No he cannot, I can say this with confidence having struggled building them on the factory floor with all of the specialized engineered tooling used during assembly. 😁 The RE-16 and family are a nightmare to get air tight which they need to be to perform correctly. Check the diaphragm for debris and clean with gentle hands and masking tape.
If you hold the disc in place and add a tiny bit of glue to where the disc touches the top of the pole piece The glue should spread in that gap there and glue it to the top of the pole piece. Where it was originally glued.
Hey Dave Diggin the channel!! Hey do you know much about a Altec 639 A mic. ( Birdcage mic ) it has a short where it plugs in I was wondering how to dis assemble the mic from housing to get a look at the wiring to figure the short Thank u .Thomas
Dave, thank you for that video! Absolutely incredible! I was holding my breath a lot of the time. I have a question about an RE10. Mine is pristine with no visible evidence of abuse, but the history is unknown. When shaken, the output includes a very low level ticking, similar to your RE10's rattle only *much* quieter and higher frequency. Do you have any specific idea what this might be, whether it's reparable, and how to proceed? Thanks again for the video and for sharing all your experience and expertise.
The school is not that hard to take out and if you're careful a sharp set of small pliers will work. I use a small vise grip plier needle nose and it can grab the side of that screw and twist it out really well
I just got a brand new RE20, how long after initially purchasing do these mic’s tend to go bad, either with this issue or the foam disintegration problem? Just wondering if it’s better to change
Another intriguing video! This was super informative as I have an RE320 that took a hit from phantom power for several hours and now no longer passes any audio, So I may tear into it and try to repair it and get it working. At this point I'd be happy if it just worked with or without the voicing switch and circuitry. If you have any advice on what the problem might be, I'll gladly take it!
Well, phantom power will not hurt that mic or any balanced dynamic mic no matter how long it is applied unless there is another issue. It is theoretically possible that if pin 1 is shorted to pin 2 or pin 3 and phantom is applied, it could damage some dynamic mics but I have not proven that to be the case with testing. Most likely there is another issue with the mic, hopefully a broken wire that can be reconnected. Let me know what ya find
@@DaveRat I haven't torn into it yet to see what's wrong, but hopefully it's nothing major. I just know the first time I connected to a channel with Phantom power, It sounded kind of shrill and scooped, But instantly sounded like it should the moment the 48 volt off. Then the second time it got hit with 48v for about 6 hours for a show because the signal was being used with a passive Y-cable between two boards, and the other board had a blanket Phantom Power switch for all the channels that drummer used for his IEM's. The mic worked when unplugged it, But didn't work the next time I went to use it.
hit it with a small DC at the capsule leads, re-solder(lead might help) the voice coil leads at the terminals and hit it with the DC again (1.5V should be plenty, this is also how we check polarity)
Great video Dave. I recently cleaned out the rotten foam and replaced with new foam purchased directly from EV. Once completed, the rattle is gone but so the low end. I did not tear down to the extent that you did, but am willing and able if this will fix the issue. It now sounds like it has a HP filter applied. Do you think this filter effect is due to the collapsed diaphragm, phase plug, or some other issue? Thanks for all the videos!
It's possible that the cloth filter on the resonator has collapsed and with new foam is pressing the diaphragm and holding it preventing full excursion. It's also possible some ferrous debris was disturbed in the refoam process and is now resting on the diaphragm. Remove the headbasket/front grille, does the low end return? If no, Check the diaphragm for debris.
Hey Dave!! I think I mess it up in one step Mine has the same rattle sound I glue it but It sound with less low end and a weird top end Also deep sounds (like a tom) make a strange sound I think it has to be with the Diaphragm that I didn’t glue well Can you help me?
No. Did you watch it all? Rotted foam is a nuisance with many microphones, more so American, and you can’t help but assume the cleanout improves the sound in some way. Good mics deserve the time and effort. European and Japanese mics frequently use elastomers for shock mounting and ultra fine metal screens for blast protection. Foam sucks up moisture that microphones are obviously subject to from use and, given time, that moisture helps the foam’s delicate structure to rot away. I wonder how many more decades for manufacturers to get the memo.
The tiny glue drop wants to flow into the place where the internal phase plug that was rattling around touches the top of the magnet. Super glue will flow into places where two things are touching. So a tiny dab of glue apied where the phase ug touches the magnet, while the phase plug is held in place. Barely any glue is needed.
@@DaveRat thank you so much.. I was jsut afraid of putting glue tht would drip through the screen and the holes and onto the diaphram.. you said you do NOT want theglue to do that SO... 'l put a drop on the edge and let in run between the magnet and that screen... got it thanks... tiny drop - got it
I have a hard time believing they couldn't design this better. As great as it sounds, this is maintenance nightmares and wasteful. How long do these usually last under normal conditions? I'd rather sell them and buy new before it happens xD I went "are you fucking kidding" several times and then you go "and then you break off the aluminium tube..." EV, stop. This is bad! It's like a prototype design that went into production.
Well, they make several newer versions that don't have all the home-made aspects, like the re27 which I have opened and re320 which I have not opened. But they lack the smooth sound. And yes, these are like a craft project nightmare
@@DaveRat Yeah, worked with them but they just don't do the trick (the trick being: there's things you need an RE-20 for...) I don't get it, there's some design elements in this that can be done better without affecting the sound...
Don't assume this is the standard repair procedure, while it may work well enough it's not how we did it at the factory nor how i do it today. I am impressed this works at all, like duly impressed.
@@myaccount9745 please consider thing was designed in the 1960s. This is like comparing a C2 corvette with a current C8 and nit picking 😂 ..if anything, it demonstrates how amazing the engineering was at the time that this design is still widely used in 2023. I have 1st gen models that work perfectly, all they need is some foam.
Hi Sir! Love your Vids! -as im constructing my -on the way to ATMOS Set- I need a rigid Woofer Magnet (no mech) For the 2nd LFE Chan. to get a nice Bump /ki!gg! in da !aSs!" - The Mono Amp is capable of ..kWs.. - mount on Mainsocket of Chair - moveable up dwn... THX for hints -Yours °;° Strike
Hi Dave,
you saved my ass with this one or the RE20 of my client!
I think I may found a fix for collapsed diaphragm, at least for those who has a loose phase plug: I removed the capsule completely, open it up as you have shown in the video, placed the capsule without resonance cap (phase plug cover) upside down on a fat rubber o-ring that touches the border of the diaphragm. Put that on peace of wire mesh on the top of the empty RE20 housing. Then put carefully some non magnetic weight (my x-acto knife is aluminum) through the back opening on the loss phase plug and force the diaphragm in an outward position. Then I took a heat gun adjusted to 100ºCelsius, with the lowest fan setting and blow from beneath at the diaphragm (via the housing with the capsule on top) for about one minute. Let it cool down, with the diaphragm still under tension. That should help with the collapsing part, but it is always a good idea, to clean the diaphragm from any metal dust that is attracted by the magnetic gap. That lets the diaphragm relax and brings back the bass.
Liebe Grüsse
Benno
Interesting and very cool
Friend, firstly, greetings from Brazil!! Second: thank you very much, I'm really happy to be able to save my mic. I glued the heart to the mic. follow the game! You were a conductor.
So cool!!!
That was freakin AWESOME!
You tackled one of the most common problems with these mics.
WOW these RE 20s are complicated!
You did a great job!
Thanks!
Thank You Jon Anderhub !!!!
You have explained the workings of the capsule more clearly than any engineer I've worked with at EV.
That capsule is sealed and airtight much like how the RE-16 et al must be to maintain their advertised performance. When you break the terminating cavity free you undid that air seal.
I believe the tubes are aluminum not brass. (could be wrong) ..we called them "cigarettes" and they've changed over the years in how they're "tuned."
The "rotting foam" inside the capsule is a damping plug and we use airflow and a meter to tune it (with the diaphragm removed) to a specified impedance. I agree, the older models which used fiberglass are far superior in that they do not rot and they can be reused/retuned. The smart cookies playing along at home may have concluded that they can replace the foam that rotted out with fiberglass, but what size? how to tune? Do you leave it empty? How is the low end response, more/phatter low end or is it even discernible? I have a sneaking suspicion we're going to end up with a 2nd hand market of bottom heavy mics out here aren't we :D (that might be a good thing)
If you get any ISO or other solvent on that voice coil it may fall apart as it is an air coil held together with an adhesive that is sensitive to alcohol.
The cloth which is adhered to the back of the pole piece (loose disk) is tuned with air-flow and a varnish that may or may not change with QuTip and alcohol cleaning.
Completeley fucking metal repair approach \m/ I saw them doing similar on groupdiy and am thoroughly impressed at the solution. Seriously awesome!
While I do NOT condone this method, one slip up with that glue and it's curtains, if you find the outcome is adequate I'm stoked for ya and for finding a field repairable solution that is "good enough."
Dave, have you sent one of your repaired mics into Bosch/EV and had them sweep it on the factory floor to see how close to spec your repaired mics are? Thoroughly interested. I could help facilitate.
Bless up 🙏 inspired me to make some vids and help anywhere I can....kinda buried in repairs tho 😊 (sorry if I haven't returned emails I've been watching to see if Dave had a more expedited solution which I find the answer was no but it was very impressive and can't hate on that at all)
Thank you for all the great info! Yeah, this is a last ditch fix as I believe if this fails, the only other option is to replace the capsule
I do believe there could be some shifts due to the repair, it does appear that the broken seal gets pretty well or very well re sealed as the old glue seems to act like a gasket to some degree.
I think I recall the XLR male on the RE16/15 being glued as well. If that is the case, now I understand why, the air leak. Possibly it was a diff mic with the red glue on the XLR.
Thanks again and really appreciate the comments and knowledge!
Hey dave , mezmorizing vid , u have the hands of a surgeon, how in blue blazes u remember the inner workings of these microphones just astounds me , consider my mind blown , awsome!!!!!!!!!!!!!!!!!!!!
Thank you Stephen!
Thank you so much! I had my mic with that problem for years and there seemed to be no fix for that. Your video was extremely helpful and now I have a fully working PL20/RE20 again.
Awesome!!
What a pain! I had a PL20 with that problem that I wound up selling as non-working due to the cost of repair. I have 3x RE320s that I like very much but this video has convinced me to never buy another.
👍😃
Just saved myself $300 by doing this! Thank you
I enjoyed that! I had a good time fixing an ancient D202 during lockdown that had a broken wire on its front capsule humbucking coil.
Super cool
@@DaveRat it was a head scratcher as it was in bits with snapped wires everywhere to this daughter board attached to the rear port tube - and all I had was a low res circuit diagram from the grainy brochure pdf you can find on line. Great mics tho!
That's fun solving the tricky ones
Thank you for this! I have an RE20 here that has started to do intermittent pops and static sound. Using this video I opened up the back and saw the green wire had been squished so hard somehow that some of the metal was coming through the wires insulation. I didn't want to deal with trying to replace the wire, so I just wrapped a bit of electrical tape around it to see if that fixes it. So far so good! This mic just lives on a boom stand on my desk, so hopefully the fix will work for a while.
Perfect and that should work just fine!!
Thank you for sharing this Dave! I successfully repaired 2 RE20's following along with you and they are back in business.
That is awesome!!!
Regarding the 3rd video in the series I felt it fair to share my comments for the public to digest:
Very well done sir 🙏
Regarding your "honky" mic: sweep the filter circuit's frequency response and look for a deep notch where you are hearing the honk, if you don't see that notch in the passive eq that is why it sounds "honky." It's very possible the diaphragm is stuck, sometimes they can be unstuck sometimes the diaphragms are too far gone/damaged. Sometimes it's the voicecoil itself that is starting to fall out of shape or is pinched in the gap in those cases it's new voice coil time. Sometimes it's debris in the gap preventing the coil from moving and holding the diaphragm in a restricted state. This debris is often the old glue crust from the adhesive which used to hold the pole piece to the magnet.
Microphone won't pass a freq response within limits (might still sound good) if not air tight.
HPF components are the inductor only. If it goes open it can be rewound with #40AWG magnet wire, fill the bobbin. Less turns less rolloff more turns more rolloff. Modern PCB version can be rebuilt too but less common to fail. If microphone is in permanent "rolloff" check that the switch isn't stuck closed.
There are better ways to route the wires than the factory method of folding them up in the rear cup making future disassembly much easier with zero downside in performance.
Blue loctite 243 on the 9/64 rear cup screw may or may not help with accidental twisting when installing/removing from a 309a. That aluminum triangle bracket is really soft, don't over torque that screw or you will crack and break it.
The name dB is great 🥰
2020 put me years, literally years behind in repairs but I'm slowly catching up.... sorry everyone. Surely if you've watched this video you can appreciate the effort that it takes to repair, and sometimes it doesn't go this smoothly as Dave makes it look easy ☺
So cool and thank you!!
Dear Dave! I can't thank you enough for this excellent video showing me how to save my RE20! I had it lying around for a few years, because I had realized that the foam was not the only issue. I did as you showed and everything work out fine. I was very critical of the super glue advancing into the tiny spaces between the disc and the magnet by itself, but it really does and the thing is stuck tight now! I didn't have the plastic thing to stuck onto the super glue bottle so I used a thin wire and transported tiny drops of the glue onto the inner edges of the magnet and the disc. Worked! I am so happy I got this one working again. Greetings and alle the best wishes from Hamburg, Germany, where the Beatles made it big, my friend!
Awesome!!
YES!!! I have a vintage RE-20 with this exact issue. I've hat it sitting in a box for 10 years because I thought that you had to go through the front. AMAZING! CA nozzles on order!👽
Perfect that is so cool it took me 15 or 20 years to figure out that solution
I’m loving these mic repair videos, Dave. For some reason 🤣 we have a similar mic collection so your time and experience are of great benefit to me. Thanks so much!
👍👍👍 Peter Yianilos
Just did this repair last night. Thanks so much!
👍🔧👍
Fascinating, excellent to see this. I have one that if one end is raised, it feels like the entire capsule slides to the other end. Doesn't sound like the phase plug has moved. Early 90s version of the RE20. Thanks for the specifics, especially re: the tools used. Mike
Hey Hey platemod cool cool let me know if ya get it fixed
So it seems that the AKG D19 Influenced every mic that came after it... the 57 and especially the EV MICS with the actual tubes and ports. The D19 is hands down an awesome mic.
Ahead of it's time
Greetings from Switzerland! I really like your videos and that you let other people know about all the knowledge you made over the years. I would really like to see a AKG D12 repair video. There's so much to say about these mics - and everyone with experience has some other new tricks..... :-)
Thank you and I do have a couple d12s to work on that I will try and do videos about
@@DaveRat cool! Well, as far as my experience goes: These AKG mics are very very complicated. Their diaphragms are so big and thin, they can cause a lot of problems....
@@DaveRat Yes D12E , it will super cool , those mic loss some bottom end , but always affraid to dissasemble ...hope you will make a video . Super Job , i will try for my RE20 that have a rattling problem on my kick ...On video i saw that you press firm on the membrane , it can't break ?
@WestFinga it won't hurt the dia as you are just pinching it between your finger and the plastic dome underneath
@@DaveRat Many thanks for the reply ...i will try the chirurgie , little affraid offcourse :) Thanks for the great videos ! Seb From France
Thank you so much for this info Dave: I ended up putting a replacement cartridge into a very similar vintage mic when I found the inner phase disc was bouncing around...look forward to seeing the reassembly video!!
👍👍👍 Nick Benjamin
This is a long shot, but after 6 years of pulling an old RE20 with the rattle from my repair pile, I finally was able to remove the set screw. I was super excited to follow along with this video and fix it, but for some reason the whole head wont unscrew. It gets about a 1/4 turn before seizing up. I think it may be some of the windscreen foam that got into the threads some how? Have you ever run into this issue???
The set screw tends to damage the threads and make it not unscrew if it was tightened really tight. I would drop a bit of oil down the set screw hole and work the grill back and forth and it should come apart unscrew
I tried the oil and it helped, but eventually had to use 2 belt wrenches to finally get it off. The rest of the repair was so easy thanks to your videos. Thanks so much for doing what you do!!!!@@DaveRat
@@DaveRat It worked, the mic lives! Thank you so much for sharing your knowledge with the world. You are a treasure, Dave
Perfect!!
That is so cool and thank you for letting me know
you are the man thank you so much! bought an older RE20 and have been trying to figure this out. followed your instructions and its fixed!
Absolutely incredible!
So many pieces. I hope you talk about the foam and where to get replacements, other than the standard ebay kit. Thanks! 👍🏼
McMaster is a great source for foam
@@DaveRat but the types of foam used, how much can you deviate from the density or what density is appropriate, etc?
The foam is pretty thin on the sides and is mainly shock mount and dust protection, any open cell thin foam will work and the sound impact will be non existent as long as the foam is not crushed to cause the cells to close. Open cell foam has no impact on low frequencies which is what comes in the sides of the mic.
The front foam is a different story as it is thick, like an inch or so. It is mainly to add distance from grill to capsule, pop protection and dust protection
The front foam should be very open cell. And the more open, the clearer the HF will be. I use a loosely rolled thinner open cell as you will see in the video that will let a bit more HF through than the original foam.
@@DaveRat Thank you Dave, that is great information! 🙏🏼
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Outstanding video, Dave. I learned quite a bit about my own mic! I was not aware of the loose internal phase plug issue (mine isn't that way, fortunately), but now I know how to fix it. Thanks!
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Outstanding!
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Nice video. I have a couple of EV PL 10s that have the rattling sound. It may be a bit above my pay grade, but I think I'll give it a try.
Thank you so much for this video. Could you please just explain in more detail where exactly the glue should be placed (and how much). Thanks!
Just a tiny amount to bleed in between the disc and the top of the magnet. You are just gluing down the disk and barely any glue is needed.
Do not get glue on the diaphragm or let is leak to the voice coil or the mix is ruined
@@DaveRat Thank you.... My problem is that I have a hard time picturing what it looks like in there. Is this correct: you go in and pass through the donut hole of the magnet and then just drop glue on one spot (any spot) where the pole piece makes contact with the magnet. The original adhesive would have been between the pole piece and the magnet, but I would just be adding a blob where they meet (via my hand pushing the pole down against the magnet). Sorry if I am getting this all wrong! Just trying to understand. Thank you!
Yeah that's right I believe.
You are gluing the disc to the top of the magnet and you're going to drop a tiny bit of glue between the disc and the magnet where they get glued together and the super glue Will automatically spread at that junction where they meet by nature as liquids do when they encounter two things close together.
The glue doesn't need to go all the way around it just needs to have a small amount applied to where the disc meets the top of the magnet and it'll spread inside of there on its own
@@DaveRat OK, Thank you!
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an excellent video ------ very well done
Thank you Thomas!
Hi,
Great video, so much so, I took on myself to delve into attempting to dismatle a very old PL20. Unfortunatley the post is broken. Not sure if I did it as I took care to lift and not twist the plug housing off the main body, but the underside has some scoring which would suggest that it has been twisted.
I appreciate if you have any suggestions on how work around the broken post issue.
In the meantime a good clean up and some new foam is in progress.
Many Thanks for sharing your knowledge & experince.
For the broken post, I have fixed that before using a threaded machine screw that fit the hole and cut the head off and to length.
That said, it is not a critical part. I believe it reduces RF and since these mics were/are used a lot for radio stations, RF is a concern more so that when used in other applications.
It serves to align the bottom to the top rotation, and forms a small inductor.
Make sure the wire is connected but beyond that, you will never notice a difference if it's floating and broken on there
@@DaveRat So as long as the wire is wrapped around the pin, we should be OK?
Yeah, that wire is acting like a low pass filter for noise at like 30k and up I am guessing
@@DaveRat Thank you for your advice. Here's to reassembying and getting it work :)
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i came back to re-watch and see if you mentioned the hex size to remove top screen, and i found that did. .09mm, i wonder if thats the same as a 0.035"? the set i have only goes down to .050. pretty small, but not small enough. i'll have to order it i guess.so glad you made these videos, thanks.
Just want to say again how awesome this solution is! \m/ "humans win" -Chunger
Thank you and great to meet ya!
Thanks for the explanation. Just wondered why after all these years they didn't come up with a solution for the foam or the loose disc? Or did they already with newer versions and I just missed it?
Yeah, we are seeing issues that they did not predict or plan to prevent happening 20 or more years down the road.
Adhesive's and foams have come a long way since way back then. Also changes to things like foams not lastonger but nearly always change the sound which may not be a loved change by all.
Do you have a repair video on akg D12 ?
Not yet but have 2 that need work
Could you do a strip down and rebuild of an RE-15 - if they can be taken apart of course? I bought one for use in my Elvis tribute and, yes, the foam had rotted. I cleaned it out and replaced it by simply removing the grill but that’s all. I’d really like to see inside it, if possible, to see how/if I can improve the sound. Or, as it actually works and I now use it in the act, would it be best to simply leave well enough alone?
No he cannot, I can say this with confidence having struggled building them on the factory floor with all of the specialized engineered tooling used during assembly. 😁
The RE-16 and family are a nightmare to get air tight which they need to be to perform correctly.
Check the diaphragm for debris and clean with gentle hands and masking tape.
Thank you
Great video, but it wasn’t clear where you’re actually applying the glue - around the outside edge of the disc? Thx!!
If you hold the disc in place and add a tiny bit of glue to where the disc touches the top of the pole piece The glue should spread in that gap there and glue it to the top of the pole piece. Where it was originally glued.
Thanks!
I’m happy to say I was able to fix it following your instructions. Thanks again. Now onto my Beyer M69!
Great help my g; I nd help opening up an EV 320 this helps me a lot. I am subbing! ✌🏽
Welcome And thank you!
Hey Dave Diggin the channel!! Hey do you know much about a Altec 639 A mic. ( Birdcage mic ) it has a short where it plugs in I was wondering how to dis assemble the mic from housing to get a look at the wiring to figure the short Thank u .Thomas
Thank you Thomas. Hmmm, I have not opened one of those but studying these pics may help ya get inside
coutant.org/altec639/
So cool!!
Thank You Mark Nicholson
Dave, thank you for that video! Absolutely incredible! I was holding my breath a lot of the time. I have a question about an RE10. Mine is pristine with no visible evidence of abuse, but the history is unknown. When shaken, the output includes a very low level ticking, similar to your RE10's rattle only *much* quieter and higher frequency. Do you have any specific idea what this might be, whether it's reparable, and how to proceed? Thanks again for the video and for sharing all your experience and expertise.
Sounds like something's loose inside there Little piece of debris banging against the diaphragm.
Need to open it up and take a look
@@DaveRat I was afraid of that. I'm just getting ready to order a pair of Vampliers so I can get the *&%^#@ screw out. Thanks.
The school is not that hard to take out and if you're careful a sharp set of small pliers will work. I use a small vise grip plier needle nose and it can grab the side of that screw and twist it out really well
I just got a brand new RE20, how long after initially purchasing do these mic’s tend to go bad, either with this issue or the foam disintegration problem? Just wondering if it’s better to change
10 to 20 years on the old ones. No one knows on the newer ones, will need to wait 10 to 20 years to find out
Can you repair Telefunken U40?
Another intriguing video! This was super informative as I have an RE320 that took a hit from phantom power for several hours and now no longer passes any audio, So I may tear into it and try to repair it and get it working. At this point I'd be happy if it just worked with or without the voicing switch and circuitry. If you have any advice on what the problem might be, I'll gladly take it!
Well, phantom power will not hurt that mic or any balanced dynamic mic no matter how long it is applied unless there is another issue. It is theoretically possible that if pin 1 is shorted to pin 2 or pin 3 and phantom is applied, it could damage some dynamic mics but I have not proven that to be the case with testing.
Most likely there is another issue with the mic, hopefully a broken wire that can be reconnected. Let me know what ya find
@@DaveRat I haven't torn into it yet to see what's wrong, but hopefully it's nothing major. I just know the first time I connected to a channel with Phantom power, It sounded kind of shrill and scooped, But instantly sounded like it should the moment the 48 volt off. Then the second time it got hit with 48v for about 6 hours for a show because the signal was being used with a passive Y-cable between two boards, and the other board had a blanket Phantom Power switch for all the channels that drummer used for his IEM's. The mic worked when unplugged it, But didn't work the next time I went to use it.
Sounds like a short between pin 1 and pin 2 or pin 1 and pin 3 in the Y or somewhere. That would cause exactly what you experienced.
hit it with a small DC at the capsule leads, re-solder(lead might help) the voice coil leads at the terminals and hit it with the DC again (1.5V should be plenty, this is also how we check polarity)
Great Video. 😃👍♥️
Thank You Kevin Petit
@@DaveRat Your Welcome 😃
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Great video Dave. I recently cleaned out the rotten foam and replaced with new foam purchased directly from EV. Once completed, the rattle is gone but so the low end. I did not tear down to the extent that you did, but am willing and able if this will fix the issue. It now sounds like it has a HP filter applied. Do you think this filter effect is due to the collapsed diaphragm, phase plug, or some other issue?
Thanks for all the videos!
Sounds like a collapsed diaphragm but need to open to look. Could be metal particles on the dia, that when removed, will sound better
It's possible that the cloth filter on the resonator has collapsed and with new foam is pressing the diaphragm and holding it preventing full excursion. It's also possible some ferrous debris was disturbed in the refoam process and is now resting on the diaphragm. Remove the headbasket/front grille, does the low end return? If no, Check the diaphragm for debris.
when dropping the glue inside Where do you actualy put it?? on the edges? in the center??
Hey Dave!! I think I mess it up in one step
Mine has the same rattle sound
I glue it but
It sound with less low end and a weird top end
Also deep sounds (like a tom) make a strange sound
I think it has to be with the Diaphragm that I didn’t glue well
Can you help me?
Sometimes the a metal part is broken and much harder to fix.
Was the rotting foam the cause of the defect?
Great stuff as always.
No. Did you watch it all? Rotted foam is a nuisance with many microphones, more so American, and you can’t help but assume the cleanout improves the sound in some way. Good mics deserve the time and effort. European and Japanese mics frequently use elastomers for shock mounting and ultra fine metal screens for blast protection. Foam sucks up moisture that microphones are obviously subject to from use and, given time, that moisture helps the foam’s delicate structure to rot away. I wonder how many more decades for manufacturers to get the memo.
Thank you Peter
Anton, the issue with that mic was a loose disk under the phase plug and I show how to fix it
Cool.
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Hey Dave, did EV just use cheap foam inside the head, or does that foam just have a limited lifetime? (And if so, how long does that stuff last?)
The foam lasts a long time, the sound of spit and moisture on foam makes a mic feedback easier
Steady hands 👍
Hey Hey Shane Elson cool cool
Where d actually place the glue on the inside...??
The tiny glue drop wants to flow into the place where the internal phase plug that was rattling around touches the top of the magnet.
Super glue will flow into places where two things are touching. So a tiny dab of glue apied where the phase ug touches the magnet, while the phase plug is held in place.
Barely any glue is needed.
@@DaveRat thank you so much.. I was jsut afraid of putting glue tht would drip through the screen and the holes and onto the diaphram.. you said you do NOT want theglue to do that SO... 'l put a drop on the edge and let in run between the magnet and that screen... got it thanks... tiny drop - got it
Awesome let me know how it works out
I have tried my whole life to sound human.
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u n me both
@@lincolnmicrophonellc You just have to lie to these humans man. "Yes I like your band." "Yes I love my wife." They make it so hard.
I have a hard time believing they couldn't design this better.
As great as it sounds, this is maintenance nightmares and wasteful.
How long do these usually last under normal conditions? I'd rather sell them and buy new before it happens xD
I went "are you fucking kidding" several times and then you go "and then you break off the aluminium tube..."
EV, stop. This is bad! It's like a prototype design that went into production.
Well, they make several newer versions that don't have all the home-made aspects, like the re27 which I have opened and re320 which I have not opened. But they lack the smooth sound.
And yes, these are like a craft project nightmare
@@DaveRat Yeah, worked with them but they just don't do the trick (the trick being: there's things you need an RE-20 for...)
I don't get it, there's some design elements in this that can be done better without affecting the sound...
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Don't assume this is the standard repair procedure, while it may work well enough it's not how we did it at the factory nor how i do it today. I am impressed this works at all, like duly impressed.
@@myaccount9745 please consider thing was designed in the 1960s. This is like comparing a C2 corvette with a current C8 and nit picking 😂
..if anything, it demonstrates how amazing the engineering was at the time that this design is still widely used in 2023. I have 1st gen models that work perfectly, all they need is some foam.
sounds like a maraca.
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Etrange design...
👍👍👍 Octave Stud
The year is 2023, we are still using a microphone designed in the early 1960s it's a work of art.
Hi Sir!
Love your Vids! -as im constructing my -on the way to ATMOS Set- I need a rigid Woofer Magnet (no mech) For the 2nd LFE Chan. to get a nice Bump /ki!gg! in da !aSs!" - The Mono Amp is capable of ..kWs.. - mount on Mainsocket of Chair - moveable up dwn... THX for hints -Yours °;° Strike
??? 👍👍👍 Samson Strike